1. Field of the Invention
The present invention relates to a coordinate input system for use in operating a cursor or window on the screen, and a method of controlling the coordinate input system.
2. Description of the Related Art
Heretofore, mouses and track balls have been generally used as pointing devices connected to computers. In addition, other types of pointing devices called pads, touch pads, track pads, etc. have also been employed recently.
In practical use, those pads are built in portable personal computers (so-called note type personal computers), in embedded conventional keyboards, or externally connected to desk top computers. Because of not requiring to be moved in themselves unlike mouses, those pads have a feature that they can be operated without problems even in a limited space on a desk or the like.
To move a cursor (or also called a pointer) on the display screen of a computer by using such a pad, it is only required for a user to put a finger on a flat operating surface several centimeters square provided on the pad and then slide the finger while keeping contact with the operating surface. Similarly to a mouse, a pad includes a left button and a right button. In addition, as with the case of clicking the left button, various operations such as selecting and moving an object displayed on the screen, for example, an icon (i.e., a symbol pattern representing the function of an application program) or a window (i.e., any of multiple independent screens indicated on a display), can also be performed by softly tapping the operating surface with a finger.
An action of carrying out those operations in such a manner is here called "tap (action)" or "tapping". By utilizing the above tap function, a pad makes it possible with one finger to perform not only the above-stated operation equivalent to clicking of the left button, but also other operations equivalent to double clicking of the left button (used to, e.g., start up an application program), in which the left button is clicked twice successively, and dragging to move an object displayed on the screen, such as an icon or window, from one position to another desired position on the screen.
Meanwhile, when pads are embedded in conventional keyboards, an operating surface is arranged, for example, adjacent cursor moving keys (arrow keys) on the side nearer to the user. Also, when pads are built in note type personal computers, an operating surface is arranged in a space adjacent a keyboard on the side nearer to the user where fingers of the user are placed. In other words, the operating surface of a pad and the keys of a keyboard are arranged in fairly close relation, and this arrangement increases a possibility that the user may touch the operating surface of the pad by mistake during the key input operation.
Because such a false operation is regarded as a tap action by the computer, there occur troubles in work of the user under progress. Suppose, for example, that the user starts up a word processor and operates keys to make a composition in Japanese, if the tap action is performed before the key input operation is not yet completed, input letters are settled as they are without undergoing processing for conversion from kana (Japanese syllabic alphabet) into kanji (Chinese characters). Although the user intends to, for example, input a word " (computer in kana)" and convert it into " (computer in kanji)", "" in kana is settled on the screen as it is without being converted from kana to kanji.